Overdrive control system



E. M. CLAYTOR QVERDRIVE CONTROL SYSTEM Fild Nov. 20, 1940 3 ATTORNEY,

Paiented ay 1, 1942 ovnnnarvn coN'raoL srs'raiu ATET corporation oi Delaware Application November 20, 1940, Serial No. 366,441 4 Claims. (Ci. 192-3) This invention relates to systems of control for automobile overdrives and particularly the type of overdrive which employs a planetary gear. When the overdrive is operative, the sun gear of the planetary gearing is held stationary by a pawl, the movement of the pawl is controlled by an electromagnet generally known as the overdrive solenoid. To come out of overdrive the pawl is retracted from the sun gear. The retraction of the pawl from the sun gear is facilitated by interrupting the engine ignition.

In systems of electrical control of overdrives which have been used, an electromagnet relay switch is used to control the overdrive solenoid and a second relay switch controlled by the first relay switch is used to control the ignition. It is an object of the present invention to provide a single relay controlled by a driver operated switch for controlling the overdrive solenoid and forcontrolling contacts in the ignition circuit, said single relay being provided with means for delaying the return of the ignition controllingcontact to normal condition for a predetermined time after the driver operated switch is operated.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing wherein preferred embodiments of the present invention is clearly shown.

In the drawing:

Fig. l is a wiring diagram illustrating the use of a single relay for controlling an overdrive solenoid and for controlling contacts which are operable to disconnecirthe ignition apparatus from the current source.

Fig, 2 is a wiring diagram illustrating the use of a single relay for controlling the overdrive solenoid and for controlling contacts in an ignition grounding circuit.

Referring'to Fig. 1 an overdrive solenoid 20 comprises a stationary core 2| mounted on a support 22 in alignment with a movable solenoid armature 23 guided by a support 24 Armature 23 receives a nut 25 urged against a stop 26 by a spring 21 located between the nut and the support 25. Armature 23 provides a cavity for receiving a spring 28 located in a state of compression between the nut 25 and a shoulder 29 provided by a pawl rod 30 extending thru the armature 23 of the core 2! and the support 22 and attached at its lower end to a pawl 3i which, as shown in'Fig. 2, is adapted to engage a blocker plate 32 and a locking ring of a sun gear 36. When the solenoid is energized to cause the armature 23 to move downwardly toward the core 2i the spring 28 is further compressed to cause the pawl 3! to bear against the blocker 32. During a reversal of torque between engine and transmission the blocker 32 moves away from the lower end of the pawl 31 to allow it to engage the sun gear locking ring 33. Finally the pawl engages a notch in ring 33- and holds the sun gear stationary thus placing the overdrive in operating condition.

The armature 23 of solenoid 20 is caused to move downwardly against the action of spring 21 by the combined efiect of electromagnet coils 35 and 35 the former being the main attracting coil and the latter the holding coil. During the downward movement of armature 23 the fiang'e or the nut 25 engages a contact blade 3! which s separates a grounded contact 38-from a contact 39 connected with coil thus open-circuiting the main attracting coil. However the armature 23 will be held down by the holding coil 36 so long as the latter is. energized.

The system of control of the solenoid 2B and of the ignition circuit includes a relay 40 having strikes againstthe non-magnetic projection 43 thus holding the armature spaced from the core 62 so that it will not seal against it. Therefore the return of thearmature it to normal posi.

tion is not appreciably retarded when the relay to is deenergized.

Relay 80 has an armature 56 connected with a terminal 5| and carrying a contact 52 adapted to engage a contact 53. When the armature 50 is attracted toward the core 42 it will seal against it. Therefore armature 50 will remain in engagement with the chromium plated head 42 of core M for an appreciable length of time following the separation of the armature M from the projection G3. The core 4! is surrounded by an energizing coil 54 in shunt with a resistance 55 having the efiect oi retarding the decay of flux in the relay when coil 54 is disconnected from the current source. The retardation of flux decay may be further increased by the use of a short circuited coil 56.

The connection of the coil 54 of relay 40 as well as the holding coil 36 of solenoid 2G with a current source such as battery 58 is controlled by a control circuit including a gear switch 60 having stationary contacts GI and 62 adapted to be bridged by movable contact 63 normally held open by spring 62. When the regular transmission of the automobile is in intermediate or high condition the switch 80 will be closed.

Switch '69 is connected with a kick switch 65 having contacts 66 and ti normally bridged by contact 88 held up by spring 69. Contact 58 may be pressed downby rod 88a associated with the throttle or accelerator pedal in such relation that, when the pedal is pressed to the extent required for quick acceleration, the switch 65 will be opened.

Switch 65 is connected with a speed responsive switch 13 which may be: any suitable form of switch or may be the air vane switch 13. Switch 13 is pivoted at 12 and is held by a spring 13 normally against a stop 14. Switch 1| carries a contact 16 adapted to engage a contact 16 connected to a common terminal 11 with which magnet coils 54 and 36 are connected in parallel. Vane 1| is caused to move clockwise by the impingement thereon of a" current of air represented by arrow 11 caused to circulate by the engine cooling fan 13. At a predetermined speed such as 25 M. P. H., for example, switch 13 will be closed. If the regular transmission is in intermediate or high the switch 63 will also be closed. Then current will flow from the battery 53 thru the coil 54 of relay 43 into the coil 36 of solenoid 23. At that instant, however, the solenoid armature 23 will not move downwardly since the'energization of the coil 36 is not sumcient to overcome spring 21.

attracted toward the core 4|. The closing of contacts 41 and 43 will complete the circuit from the battery to the ignition switch 33 and thence to the ignition apparatus independent of the Coil 54,. being connected with the current source, armatures 44 and 53 will be contacts 52 and 53. Therefore ignition will be provided altho the contacts 52 and 53 are separated. The closing of contacts 46 and 46 establishes a circuit between the battery 53 and the main attracting coil of-solenoid 23. The solenoid 23 then operates to move the pawl 3| against blocker ring 32 (shown in Fig. 2), with yield operation reference is made to my co-pending' application S. N. 290,356, filed August 16, 1939. When it is desired to come out of overdrive the driver presses the accelerator pedal down sufficiently to cause the opening of switch 65 1 therebydisconnectlng coils 54 and 36 from the battery 53. Since coil 35 of solenoid 23- had already been disconnected as a result of downward movement of pawl rod 33, armature 23 cannot now be held down since magnetic attraction has been eliminated. Therefore spring 21 will re-" tract the pawl 2|. provided pressure is relieved between thesun gear blocking ring 33 and the pawl. This relief of pressure is efiected bymolieved to be an advantage since the engine can mentary interrupting the ignition. According to contacts 52, 53 willbe opened while contacts 41,. v 4.3 areclosed. Therefore the current flow 'between the battery 58 and the. ignitionapparatus will be interrupted. During this interval the.

pressurebetween the pawl" 3| and the sun gear locking ring-.33 will be relieved so that spring 21 of the solenoid'23 is able to retract the pawl 3|.

However, if the pawl 3|; should not be'disengaged from the ring 33 ignition willretracted ja 35 thereby energizing: the overdrive solenoid 23 i in any event since the ignition controlling contacts 52, 53 will return to normal condition at a predetermined time following the opening movement of the switch 55. a

In the form of an invention shown in Fig. 2 I employ a single relay 33 having a core 3| with a chromium plated end or pole and having an armature 32 connected with a terminal 33 and arranged to seal against the chromiumplate pole of the core 3| when the armature is attracted. Armature 32 carries contact 34 adapted to engage a contact 35. When contacts '34, 35 are engaged the battery 53 is connected with solenoid terminal 231; with which the attracting coil 35 and the holding coil 33 are both connected. Armature 32 insulatingly supports a contact 33 for engaging a contact 31 connected by wire 33 with spring blade 33 havingan insulating button 33 normally bearing against the upper end of the pawl rod 33.. Blade 33 carries a contact 3| adaptedto engage a grolmded contact 32 when the pawl rod 33 moves downwardly. Contact 36 is connected by wire 33 with a point 34 intermediate the primary coil 35 of ignition coil 36 and a timer 31 which .is grounded. Primary 35 is connected with battery 53 to a switch 33. The secondary winding 33 of coil 35 is connected with an ignition distributor not shown.

Relay core 3| is surrounded by magnet coil I33 in parallel with a resistance l3! employed for the purpose of retarding flux decay in the relay when coil I33 is disconnected from battery 53.

The connection ofcoil I33 withbattery 53 is controlled by a system of switches including the gear switch 63, the kick switch 65 and some form of speed responsive switch such as the switch H3 shown in Fig. 2. Switch 3 is of the vane type and employs a vane pivoted and grounded at 2 and urged normally by. a spring 3 against a stop 4. Vane carries contacts H5 and 6 adapted to engage respectively with resiliently mounted contacts 1 and 8 connected respectively with terminals 3 and |23. Terminal 3 is connected with contact 61 of switch 65; and terminal I23 is connected with contact 62 of switch 63. The spacing of contacts H5, H1 and contacts 6, H3, and the calibration of the spring 3 are such that contacts 5 and 1- close during the lower speed range, for example 25 M. P. H. and the contacts H6, 3 close in the upper speed range, for example at 55 M. P. H. It is therefore apparent that the driver has control of the overdrive at a speed below the speed at which contacts H6, 3 close. Above that speed the car can not be taken out of overdrive. This is beoperate most eiliciently to propel the car at the higher speeds when the transmission is in overner similar to that described in connect-ion to {that of .Fig. 1. Whe'na speed of 25 m.'p, h.,'i'or example has been reached,,the switch 3 closes; thereb'y'eauslng relay-coil I33 to be. connected with battery provided the gear switch 33 1s closed which will be the case if the transmission is in intermediate or high condition. The arma ture 32 will then beattracted downwardly to seal against the core 3|- andto close contacts 3| and value, such azeaeas to condition the pawl for going into overdrive when the driver releases the accelerator pedal sufliciently to permit the engine speed to fall a certain percentage below the car speed. As the pawl 30 moves downwardly contacts 9| and 92 engage; but the ignition coil 96 i not then grounded because the downward movement of armature 82 has separated the ignition controlling contacts 86 and 81.

To come out of overdrive with the system shown in Fig. 2, the operator depresses the accelerator pedal sufliciently to open switch 65. Due to the fact that the decay of flux in the relay 8D is retarded due to the use of the resistance llll and due to the fact that armature 82 seals against the core 8|, the upward movement of the armature 82 to normal position is delayed for an appreciable length of time following the opening of the switch 65. Therefore the reclosing of contacts 86 and 81 as well as reopening of contacts 8d, 85 is delayed. The length of this delay (on the order of .1 to .2 seconds or even longer if desired) is sufficient to allow the engine to pick up in speed sufliciently to deliver positive torque'to the overdrive instead of negative torque before the ignition coil is short circuited by the reclosing of contacts 86 and 81. If the car driver should press the accelerator pedal down in the normal waythere would be sufficient delay in his foot action to enable the engine to give the positive torque. The system shown in Fig. 2 takes care of the condition when the driver presses the accelerator pedal down as fast as.

possible thus opening the switch 65 before the engine has had time to accelerate from negative to positive torque. Therefore the system shown in Fig. 2 provides a period of time following the opening of switch 85 during which the solenoid 20 remains energized and the ignition remains operative. While the solenoid 20 is energized, the contacts SI and 92 are closed; and the instant contacts 86 and 81 reengage the ignition will be short circuited, thereby relieving the pressure between the sun gear locking ring 33 and the pawl 3| in order to facilitate the retraction of the pawl 3| by the spring 31. By the time the pawl 3| has been retracted, contacts 9| and 92 will be separated so that the ignitionshortcircuit is broken and operation of the engine is resumed. I

From the foregoing description of the construction and method of operation of the two systems embodying the present invention, it is apparent that I have provided a single relay under the control the driver operated kick switch for controlling both the overdrive solenoid and for controlling contacts which control'the ignition apparatus. This relay has means for retarding the return of the ignition circuit controlling contacts to normal status for a predetermined time following the operation of the kick switch. In the case of the system shown in Fig. 1, during this period of delay following the opening of the kick switch 65, of the return of the ignition controlling contacts to normal status, the ignition is inoperative; Operation of ignition is resumed when the contacts return to normal status. In the case of the system shown in Fig. 2. during the delay period of following the opening of the kick switch 65, the overdrive solenoid and the ignition remain operative in order to givethe engine opportunity to deliver positive ratus,

torque before coming out of overdrive. At the controlling the overdrive pawl, ignition appa- I ratus, a driver operated control switch, and a single relay controlled by said driver operated switch and operable for controlling the overdrive solenoid and for operating contacts which'control the status of the ignition apparatus, said relay having time lag provisions for delaying the return of the ignition controlling contacts to normal status for a predetermined time following operation of the driver operated control switch;

2. An overdrive control system comprising a current source, an overdrive pawLa solenoid for controlling the overdrive pawl, ignition apparatus, a driver operated control switch, a single relay controlled by said driver operated switch and having normally closed contacts establishing an ignition circuit and having normally open contacts for connecting the current source with .the overdrive solenoid and having normally open contacts which, when closed, will by-pass the opened (normally closed) ignition controlling contacts, said relay having time lag provisions for delaying the return of the ignition controlling contacts to closed status for a predetermined time following operation of the driver operated I switch.

3. An overdrive control system comprising a current source, an overdrive pawl, a solenoid for controlling the overdrive pawl, ignition apparatus, a driver operated control switch, an ignition grounding circuit'including a pair of normally closed contacts and a pair of normally open contacts, the latter being controlled by the solenoid, and a single relay controlled by said driver operated switch and including the normally closed contacts of the ignition groundin circuit and including a Pair of normally open contacts for connecting the current source with the overdrive solenoid, said relay having time lag provisions for delaying the return of the relay contacts to normal status for a predetermined time following operation of the driver controlled switch. i

4. An overdrive control system comprising a current source, an overdrive pawl, a solenoid for controlling the overdrive pawl, ignition appaing a magnet coil connected with the current source through the driver operated switch, and

having contacts for connecting the current EDWARD M. CLAYTOR.

a driver operated switch, and a relay hav- 

